Method for Trimming Molds of Automotive Metal Sheets

ABSTRACT

The present invention provides a method for trimming molds of automotive metal sheets, which comprise a top mold and a bottom mold. The top mold has a concave mold surface, and the bottom mold has a corresponding convex mold surface. The method comprises: 1. Use the top mold as the base mold, and smear dye on the top mold; 2. Close the bottom mold to the top mold; and 3. Polish the mold surface of the bottom mold. Thereby, the processing method according to the prior art is broken through, and an ergonomic trimming operation is hence provided. Accordingly, the trimming process is simplified, and the labor hours are reduced. Beside, the accuracy of trimmed molds is improved and the subsequent mold-clamping process can be omitted. Thereby, the exterior quality of the metal sheets can be enhanced while reducing substantial labor hours, and economic benefits for manufacturing molds of metal sheets for an automotive body can be achieved.

FIELD OF THE INVENTION

The present invention relates generally to a method for trimming moldsof automotive metal sheets, and particularly to a method for trimmingusing a top mold as the base. Thereby, the exterior quality of the metalsheets can be enhanced while reducing substantial labor hours, andeconomic benefits for manufacturing molds of metal sheets for anautomotive body can be achieved.

BACKGROUND OF THE INVENTION

The automotive industry is an important basic industry for modernpeople's livelihood. It is a common knowledge that an automobilecomprises a great amount of components with various sizes. Most metalcomponents are mass-produced via molds. For large-sized automotive metalsheets, according to the prior art, after an automotive metal sheet isshaped by stamping using a mold of large-sized automotive metal sheet,if flaws or deviations exist in size or appearance, they can be resolvedby polishing. In addition, there is a certain tolerance in appearance.However, because modern automobile manufacturers' or consumers' demandon exterior quality is increasingly severe, more and more automobilemanufacturers require no polishing for avoiding zinc-plating layer onmetal sheets being polished, and thus reducing antirust capability,during the polishing operation. Furthermore, a polishing operation costsmuch in labor. Thereby, precise manufacturing and trimming of automotivemetal sheets has become a crucial subject for enhancing exterior qualitywhile maintaining economic benefits.

Please refer to FIGS. 1A, 1B, and 2. The stamping molds used for shapingmetal sheets of an automotive body according to the prior art comprise atop mold 91 and a bottom mold 92. The top mold 91 has a proper form usedfor shaping, and exhibits roughly a concave mold surface 911. The bottommold 92 has a proper shaping form corresponding to the top mold 91, andexhibits roughly a convex mold surface 921. As shown in FIG. 3, whenstamping a metal sheet for an automotive body, a steel plate 93 isshaped by stamping by means of the top and bottom molds 91, 92 and thusthe manufacturing of a metal sheet for an automotive body 94 iscompleted as shown in FIG. 4. Because the top mold 91 and bottom mold 92are the principal parts when stamping a metal sheet for an automotivebody 94, the manufacturing accuracy and efficiency have decisiveinfluences on the quality, economic benefits, and competitiveness ofstamping a metal sheet for an automotive body 94. The procedure of themanufacturing technology for stamping molds for metal sheets of anautomotive body according to the prior art includes: acquirement ofdesign drawings and CAD (Computer-Aided Design) data, design ofmanufacturing method, design of molds, manufacturing of Styrofoam,manufacturing of casts, NC (Numerical Control) programming, processingby large-sized machines, trimming (shiage), mold clamping, mold trial,and quality management (measurement and appearance judgment of metalsheets). The trimming process of the stamping molds (the top mold 91 andbottom mold 92) described above mainly performs polishing process on thestamping molds, referring to FIGS. 5 and 6, and includes the followingprocedure:

-   -   1. Take the bottom mold 92 as the base mold, and smear red lead        (step 96 in FIG. 5) on the bottom mold 92. That is, use the        bottom mold 92 with a convex mold surface 921 as the base mold,        and smear red lead 961 on the convex mold surface 921.    -   2. Reverse the top mold 91 to make the surface of the top mold        91 face up (step 97 in FIG. 5). Because the surface to be        polished and trimmed is on the top mold 91, reversing the top        mold 91 helps the process of polishing and trimming.    -   3. Close the bottom mold to the top mold 91 (step 98 in FIG. 5).        Namely, close the lifted and moving bottom mold 92 to the        stationary top mold 91. Then, the concave mold surface 911, the        surface to be trimmed, on the top mold 91 will be dyed with red        lead.    -   4. Polish the mold surface of the top mold 91 (step 99 in FIG.        5). That is, trim the concave mold surface 911 dyed with red        lead on the top mold 91. The polishing and trimming tools        include: curved grinding wheels, coarse rubstones, grinding        wheels with handles, pen-type grinding wheels, files, and        wetstones.

The trimming process on molds for automotive metal sheets according tothe prior art as described above can trim the molds for metal sheets ofan automobile. However, there exist some significant drawbacks accordingto the method. For example, according to the prior art, the bottom moldis used as the base mold for polishing the top mold. Because of theconcave mold surface of the top mold (including complicated moldshapes), the operation of polishing and trimming the concave moldsurface does not comply with ergonomics. Thereby, the operation isdifficult, costing long operation time, and hence is not economic.Beside, because the mold surface of the top mold is concave, it tends todeform or displace while polishing the shaped surface, and thusincurring other problems in trimming. Moreover, because the trimmingprocesses are repeated operations of trimming and examinations, it takesmonths to perform the trimming processes, costing much in costs andtime. Thereby, the shortcomings of high production costs, reducedefficiencies, and uneconomic problems according to the prior-arttrimming process of molds for automotive metal sheets have to beovercome.

Owing to the shortcomings of the trimming process of molds forautomotive metal sheets according to the prior art, the presentinvention provides a method for trimming molds of automotive metalsheets with economic benefits and product competitiveness.

SUMMARY

An objective of the present invention is to provide a method fortrimming molds of automotive metal sheets. According to the presentinvention, exterior quality of metal sheets can be improved, substantiallabor hours can be saved, costs can be reduced, and hence the overallproduction efficiency and economic benefit can be increased.

Another objective of the present invention is to provide a method fortrimming molds of automotive metal sheets. According to the presentinvention, the processing method according to the prior art is brokenthrough, and ergonomic trimming operations are provided. Thereby, thetrimming process is simplified and the labor hours are shortened. Inaddition, the accuracy of trimmed molds is enhanced, and subsequentmold-clamping operation can be omitted.

The method for trimming molds of automotive metal sheets according tothe present invention trims molds for metal sheets, which comprise a topmold and a bottom mold. The top mold has a concave mold surface, and thebottom mold has a corresponding convex mold surface. In order to achievethe objectives and benefits described above, the method includes:

-   1. Using the top mold as the base mold, and smearing dye on the top    mold;-   2. Closing the bottom mold to the top mold; and-   3. Polishing the mold surface of the bottom mold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a schematic diagram of a top mold for a metal sheetaccording to the prior art;

FIG. 1B shows a schematic diagram of a bottom mold for a metal sheetaccording to the prior art;

FIG. 2 shows a schematic diagram of a top mold and a bottom mold for ametal sheet set up correspondingly according to the prior art;

FIG. 3 shows a schematic diagram of a metal sheet being stamped betweena top mold and a bottom mold according to the prior art;

FIG. 4 shows a schematic diagram of a metal sheet according to the priorart;

FIG. 5 shows a flowchart of trimming stamping molds according to theprior art;

FIG. 6 shows an operation schematic diagram of stamping molds beforeclosing up according to the prior art;

FIG. 7 shows a schematic diagram of a top mold and a bottom mold set upcorrespondingly according to the present invention;

FIG. 8 shows an operation schematic diagram of stamping molds beforeclosing up according to the present invention; and

FIG. 9 shows a flowchart of trimming stamping molds according to thepresent invention.

DETAILED DESCRIPTION

In order to make the structure and characteristics as well as theeffectiveness of the present invention to be further understood andrecognized, the detailed description of the present invention isprovided as follows along with preferred embodiments and accompanyingfigures.

Referring to FIG. 7, the method for trimming molds of automotive metalsheets according to the present invention trims molds for metal sheets10, which comprise a top mold 20 and a bottom mold 30. The top mold 20has proper shapes used for forming, and roughly has a concave moldsurface 21. The bottom mold 30, likewise, has proper shapescorresponding to the shapes on the top mold 20, and roughly has a convexmold surface 31. Referring to FIGS. 8 and 9, the method for trimmingmolds of automotive metal sheets according to the present inventioncomprises:

-   -   1. Use the top mold 20 as the base mold, and smear dye on the        top mold 20 (step 41 in FIG. 9). That is, use the top mold 20 as        the base mold, use the concave mold surface 21 as the base        surface, and smear dye 22 on the concave mold surface 21. The        dye 22 can be red lead (added with some diesel oil) or other        dying materials.    -   2. Close the bottom mold 30 to the top mold 20 (step 42 in FIG.        9). Namely, close the bottom mold 30 (moving) to the top mold 20        (stationary). By the closing operation, print the dye 22 (red        lead) to the convex mold surface 31 to be trimmed on the bottom        mold 30. Alternatively, in the present step, the top mold 20        (moving) can close to the bottom mold 30 (stationary).    -   3. Polish the mold surface of the bottom mold (step 43 in FIG.        9). That is, trim the convex mold surface 31 dyed with the dye        22 (red lead) on the bottom mold 30. Because the surface to be        polished and trimmed is the convex mold surface 31 on the bottom        mold 30, it is more ergonomic for polishing operations,        drastically simplifies the polishing operations and shortens        substantial labor hours.

In practical operations, because the trimming accuracy can be improvedat the same time, the mold-clamping operation after trimming process canbe omitted and mold trial process can be performed directly, shorteningoperation time by 2 to 3 months. Thereby, according to the presentinvention, the exterior quality of the metal sheets can be enhancedwhile reducing substantial labor hours, and economic benefits formanufacturing molds of metal sheets for an automotive body can beachieved.

The method for trimming molds of automotive metal sheets according tothe present invention breaks through the selection of the base mold orbase surface for trimming molds according to the prior art. According tothe present invention, the top mold (the concave mold surface) is chosenas the base mold, and the surface to be polished is the bottom mold(convex mold surface). Because the trimming operation on a convex moldsurface is far simpler and more convenient than on a concave moldsurface, the labor hours for trimming processes are substantiallyreduced.

Accordingly, the present invention conforms to the legal requirementsowing to its novelty, non-obviousness, and utility. However, theforegoing description is only a preferred embodiment of the presentinvention, not used to limit the scope and range of the presentinvention. Those equivalent changes or modifications made according tothe shape, structure, feature, or spirit described in the claims of thepresent invention are included in the appended claims of the presentinvention.

1. A method for trimming molds of automotive metal sheets, whichcomprise a top mold with a concave mold surface and a bottom mold with acorresponding convex mold surface, comprising steps of: using the topmold as the base mold and smearing dye on the top mold; closing thebottom mold to the top mold; and polishing the mold surface of thebottom mold.
 2. The method for trimming molds of automotive metal sheetsof claim 1, wherein the dye in the step of using the top mold as thebase mold and smearing dye on the top mold is smeared on the concavemold surface.
 3. The method for trimming molds of automotive metalsheets of claim 1, wherein the top mold and the bottom mold havecorresponding shapes thereon.
 4. The method for trimming molds ofautomotive metal sheets of claim 1, wherein the dye in the step of usingthe top mold as the base mold and smearing dye on the top mold includesred lead or other dying materials.
 5. The method for trimming molds ofautomotive metal sheets of claim 1, wherein the step of polishing themold surface of the bottom mold polishes the convex mold surface dyedwith the dye on the bottom mold.